Fixed unicode behavior for exceptions

CHANGES

@@ -14,6 +14,9 @@ Version 6.8
 - Fix crash on Windows console, see #744.
 - Fix bashcompletion on chained commands. See #754.
 - Fix option naming routine to match documentation.  See #793
+- Fixed the behavior of click error messages with regards to unicode on 2.x
+  and 3.x respectively.  Message is now always unicode and the str and unicode
+  special methods work as you expect on that platform.
 
 Version 6.7
 -----------

click/exceptions.py

@@ -9,15 +9,21 @@ class ClickException(Exception):
     exit_code = 1
 
     def __init__(self, message):
-        if PY2:
-            if message is not None:
-                message = message.encode('utf-8')
         Exception.__init__(self, message)
         self.message = message
 
     def format_message(self):
         return self.message
 
+    def __str__(self):
+        return self.message
+
+    if PY2:
+        __unicode__ = __str__
+
+        def __str__(self):
+            return self.message.encode('utf-8')
+
     def show(self, file=None):
         if file is None:
             file = get_text_stderr()